XY Carriage for a printer built of Alu Extrusions

Hello guys.

I'm in the stages of designing/planning a big large scale printer that would be made of 3030 Alu Extrusions with a 400x400 heatbed and around 1m height. I've more or less designed the whole frame and heatbed rising system and now I'm facing a dilemma. What would be the best approach for a XY carriage? Should I go with the ultimaker style system, CoreXY or some other (maybe from extrusions and then add those wheels like on a tevo tarantula? Or linear rails maybe?). I want something rigid and reliable.

[openbuilds.org]

Won't really do as the printer is a cube with the bed being on the Z axis.

Whatever design you use, ensure it won't bow over the long distance... You're looking at an axis around half a meter long once you factor in gantry size for that bed...

Extrusion usually bows less than rods... You might end up needing 14mm+ diameter rods, or a chunkier extrusion than you anticipated.. Any decent supplier will supply a spec sheet, or get yourself a dial gauge and do some experiments

Thank you for the excellent advice, bowing of the axis is not something I thought about. I see that many extrusions have a hole through the middle so I can also insert a rod inside to make it more sturdy. Would you recommend the Tevo stlye wheels or should I use linear rails for the movement? Somehow I get the feeling that the linear rails are more firm and are less loose than the wheels.

Linear rails and alu-extrusions are usually the best combination.
But also consider the different thermal expansion of both materials. On such a big printer, you might see some bi-metal behaviour.
That could be avoided by fixing the rails on one end only and make the other points floating lengthwise.
I've build and calibrated my CoreXY in a warm room and then tried to print with it in the workshop ( 10°C colder ). I had no luck, although my printer is much smaller than yours will be.

BTW: CoreXY gantry style is the way to go for your design.

So CoreXY with linear rails? I was looking for simplicity but if this is the way to go then all I can say is "challenge accepted". I'll post the prototype design when I'm done making it and I hope for some answers before ordering parts.